Design method for solar heating systems in combination with pellet boilers/stoves

In this study an optimization method for the design of combined solar and pellet heating systems is presented and evaluated. The paper describes the steps of the method by applying it for an example of system. The objective of the optimization was to find the design parameters that give the lowest auxiliary energy (pellet fuel + auxiliary electricity) and carbon monoxide (CO) emissions for a system with a typical load, a single family house in Sweden. Weighting factors have been used for the auxiliary energy use and CO emissions to give a combined target function. Different weighting factors were tested. The results show that extreme weighting factors lead to their own minima. However, it was possible to find factors that ensure low values for both auxiliary energy and CO emissions.

En beskrivning av informationsmiljö därdatumstyrda förhållanden råder : En fallstudie av en myndighet och dess informationsmiljö med rättsakter

In this study a case study was conducted at the Transport Agency. The government agency is seeking better alternatives to its current ways of keeping track of important dates stated in legal documents. The agency wants to explore the possibility for an IT-solution for keeping track on those dates. In the case study change analysis was conducted on the vehicle type approval process. Qualitative interviews were conducted with a section manager, vehicle type and component approvers, and with a system administrator and a system manager at the Transport Agency in Borlänge. The study describes an information environment in an organization in which date-controlled conditions apply and challenges with such an environment.The study also provides a proposal for designing an IT-solution for such an environment. The result that emerged showed that the information environment in terms of the legal documents and the institutions’ (EU and UNECE) websites where they are distributed is challenging for keeping track on dates. The challenges of the websites are that they are limited and complicated in terms of information search. The challenges with the legal documents are that date-controlled conditions apply. In other words, the dates themselves determine which dates and what applies and not. The legal documents are also many, retroactive, refer to each other and contain regulations for different kinds of areas, which makes difficult to find the relevant dates. The design proposal that emerged was made based on the existing IT environment at the Transport Agency. It was proposed that important key concepts are identified, categorized and realized in a database with searchability on the most important common concepts as denominators, and that it the information conforms with E-message. The developed database was based on date, date type, vehicle category, legal document, minor version and other info. A web interface was created in ASP.NET and C # for access to the database, with the message that a webbbased IT-solution should be considered.

The impact of high latitudes on the optical design of solar systems

Irradiation distribution functions based on the yearly collectible energy have been derived for two locations; Sydney, Australia which represents a mid-latitude site and Stockholm, Sweden, which represents a high latitude site. The strong skewing of collectible energy toward summer solstice at high latitudes dictates optimal collector tilt angles considerably below the polar mount. The lack of winter radiation at high latitudes indicates that the optimal acceptance angle for a stationary EW-aligned concentrator decreases as latitude increases. Furthermore concentrator design should be highly asymmetric at high latitudes.